1. Field of the Invention
The present invention relates to dental tools and more particularly to a periodontal curette for removal of diseased tissue and calculus from bottom areas of deep periodontal pockets.
2. Description of Related Art
Periodontitis is an inflammatory reaction of the gingival tissues surrounding a tooth (periodontium) of a human or other toothed animal characterized by the formation of periodontal pockets (spaces) between the gum and tooth resulting in the loss of supporting bone due to the inflammatory process. The pockets accumulate bacteria, food, and other debris which wedge between teeth, especially if the gums have receded. Such accumulations manifest their presence by becoming calcified and adhere to the tooth structure.
Periodontal therapy when pocket formation has occurred often includes surgical removal of the diseased gingival tissues and recontouring of diseased areas utilizing a curette to produce an exposed environment where calcific deposits cannot collect or gather, and that are accessible to cleaning. Essentially what is necessary is removal of granulation tissue as well as inflamed gingival tissue residing in the periodontal pocket formed by surrounding healthy bone tissue and tooth.
Curettes have traditionally been used in dentistry to remove supragingival and subgingival dental deposits, to smooth root surfaces (root plane), to remove the soft tissue lining of a periodontal pocket (gingival curettage) and to fine scale and smooth tooth surfaces after the use of other scalers. Curettes generally possess a spoon-shaped blade with a continuous cutting edge forming a rounded tip, with the face and lateral sides meeting to form the cutting edge.
Curettes are currently available having two basic blade designs, i.e universal and specific. A universal curette is an instrument designed to adapt to most areas of the dentition, by modifying hand and finger positioning. The blade of a universal curette is generally characterized by two parallel cutting edges that form a rounded tip. Specific curettes are those adapted to specific anatomic areas of the teeth with only one lateral cutting edge used for instrumentation. Blade curvature and shank angulation limit the use of each specific curette to particular tooth surfaces.
The cutting and spooning action employed in periodontal curettage manually separates and removes the diseased granulation tissue or inflamed periodontal tissues from healthy bone tissue. In periodontal curettage, it is important that healthy gingival and bone tissue not be cut away because preservation of as much of these healthy tissues as possible is important for firm tooth support.
The cutting and spooning action of the periodontist using a curette is not only tedious and strenuous because of the physical effort required in separating the sinewy diseased and healthy tissues, but also awkward due to the multiple angles of manual movement of the curette necessary around the tooth and the restricted accessibility to periodontal pockets due to overall size, configuration, and functional limitations of the mouth structure.
These constraints, including blade and shank angulation, make manual positioning and movement of the curette extremely difficult to reach, scrape, cut, spoon, and remove debris from the bottom areas of deep periodontal pockets using prior art instruments. Not only are the angles, curvatures and direction of the actual curette blade important to the procedure, but also the length and angulation of the blade-bearing distal portion compared to the longitudinal axis of the gripping area of the instrument affects the ability of the practitioner to perform side-to-side directional cutting and spooning deep within deep periodontal pockets.
Horizontal rather than longitudinal angulation of the curette disclosed in U.S. Pat. No. 5,682,665 issued to Svanberg, does not allow for full side-to-side and up and down cutting within the deep pockets.
In U.S. Pat. No. 5,169,314 issued to Long, the right angle configuration of the curette blade portion compared to the distal portion of the shank limits cutting direction and accessibility particularly within deep periodontal pockets.
U.S. Pat. No. 4,505,678 issued to Andersson discloses an acute angle of the distal portion, however, the sharp cutting edges are angularly positioned within an opening at the rounded terminal end. Due to the opening and non-curved arrangement, the curette fails to provide an adequate means by which to cut and scoop out the undesirable debris from the pocket.
It is also important that the cutting portion of the instrument not have square edges, such as disclosed in U.S. Pat. No. 1,605,321 issued to Bates and U.S. Pat. Nos. 2,552,134 and 2,818,647 both issued to Berliner, as those configurations would gouge or cut into the roots of adjacent teeth or softer bony tissue. A rounded configuration allows the blade to adapt well to tooth surfaces and minimizes tissue trauma.
Curettes are generally comprised of an elongated, rigid, thin cylindrical or octagonal-shaped body having a roughened surface area for grasping manually with the thumb, middle and index fingers and have a curved cutting blade at the distal end of a shank, and secured to one or both ends of the instrument such as is disclosed in U.S. Pat. No. 5,682,665 issued to Svanberg. Projecting from one end of the instrument body is a thin, cylindrical shank. The shank may be angled in relation to the longitudinal axis of the instrument body for positioning and manipulation purposes within the mouth. The entire instrument is usually constructed of a single piece of durable metal. The exterior surface area for grasping is configured with patterns of grooves to increase the friction and manual grip ability when holding the curette during the scaling and root planing procedures.
Curettes are characteristically used in vertical, horizontal, or oblique directions; however, due to the small space and multiple confined angles within the mouth, it is often difficult to access and optimally position the cutting edges of the curette blade within deep periodontal pockets surrounding the tooth with maximum efficiency and minimal trauma to otherwise healthy tissues.
The invention described herein has been found to greatly increase access, efficiency and ability of the dental practitioner to properly and completely perform periodontal curettage particularly within deep pockets. The invention provides a curette with a blade face planar surface substantially parallel to the connection shank longitudinal axis, enabling efficient curette blade access to and separation of diseased granulation tissue lining the pocket wall from surrounding healthy bone tissue or in between or surrounding adjacent teeth in a periodontal cavity. The rounded tip and substantially parallel configuration of the blade face surface relative to the longitudinal axis of the distal portion of the shank and the about 90 degree angle between the distal and proximal portions of the shank enhance accessibility, ease of manipulation, directional cutting and efficiency of the procedure of voiding particularly deep periodontal pockets minimizing trauma or injury to healthy tissue. Because of the above orientation, the instrument can be manipulated easily. along the base of a deep pocket in a given direction.
An apparatus for periodontal curettage including separating and removing diseased granulation tissue from healthy tissue in a periodontal pocket or cavity is provided. The invention is a rigid, elongated, thin cylindrical or octogonally-shaped body with at least one proximal shank and a distal shank having a spoon-shaped, rounded tip blade at the terminal end. The spoon-shaped blade face is less than or equal to 1.2 mm in width. The planar surface of the blade face is substantially parallel to and coaxial with the longitudinal axis of the distal shank. Although the blade face is parallel to the longitudinal axis of the blade and distal shank, the blade face orientation circumferentially around the distal shank can be in any direction and is selected based on the directional relationship of the shaft (handle), proximal and distal shanks and desired cutting direction. Four different blade face orientations, 90xc2x0 apart on four different curettes can allow cutting and spooning motion in a deep tissue pocket in four desired directions, i.e., left to right, right to left, front to back, and back to front.
The configuration of the distal shank portion of the curette is preferably at about a ninety-degree angle to the proximal shaft portion and of sufficient length to enhance accessibility of the curette tips to the depth extremes of highly diseased periodontal pockets.
Instruments can be constructed in multiple embodiments wherein the spoon-shaped blade faces of the curettes are oriented substantially parallel and coaxial with, and rotated at 90 degree increments about the distal shank for specific manual, directional movement of the blade within a diseased pocket, allowing the periodontist to choose a specific blade face orientation for a specific direction of cutting and spooning in a particular pocket, i.e., left to right, right to left, front to back, and back to front.
It is the object of this invention to provide a hand-held curette that increases the manual efficiency, accessibility, visibility, and maneuverability while performing periodontal curettage, particularly in deep infra bony pockets, expand directional scraping and curetting abilities without increasing trauma or excessive removal of surrounding healthy bone tissue.
In accordance with this object and others which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.